Measurement of the refractive index and thermo-optic coefficient of water near 193 nm

We present accurate measurements of several important optical constants of high-purity water for wavelengths near 193.39 nm at 21.50°C: the absolute refractive index n = 1.436 62(2), the dispersion dn/dλ = −2.109(17)×10−3 nm−1, and the thermo-optic coefficient dn/dT = −1.00(4)×10−4 (°C)−1. We determine these values by two independent approaches, the minimum deviation prism method and an interferometric technique, and find that they give mutually consistent results.